1. Field of the Invention
The present invention relates to a structure for transmitting signals of PCI express (Peripheral Component Interconnect Express) and a method thereof; in particular, to a structure for transmitting signals of PCI express for testing the circuit with the PCI express and a method thereof
2. Description of Related Art
As the ability of processing data of the elements in computer systems has been improved, PCI express (Peripheral Component Interconnect Express) is developed for transmitting high speed data. PCI express is a new generation PCI that is compatible to the old PCI and the data transmission rate is highly increased.
In order to assure the mother board with the PCI express be operated normally, signal quality test is performed. A bus or an integrated circuit adaptor is connected with the PCI express on the mother board to input test signal and receive the return signal. The bus usually also has a function for extending signal.
During test, a lot of factors, such as signal interference, signal attenuation, sort of test fixtures, etc, must be considered to prevent the test from being wrong. According to experience, the different test fixture, especially for signal transmission bus will generate different eye diagram, will affect the test result. When different test tools are used to test the same product, the test results also maybe different. Therefore, the bus for transmitting signals is a key factor for testing.
Furthermore, PCI express is used for transmitting high speed signal. The first generation PCI express had a bandwidth of 2.5 GB per second for one data channel in one direction. The signal will be interfered or attenuated so that the testing process is unstable when the bus becomes longer. Therefore, the cost of the bus for PCI express is expensive.
How to provide a cheap and stable signal transmission and method for PCI express test is a major concern for the manufacturer.
To address the above issues, the inventor proposed a new structure and method for transmitting PCI express signals.